import java.util.Scanner;

public class Testdemo {
    public static void main(String[] args) {
        Scanner sc =new Scanner(System.in);
        String a=sc.nextLine();
        if(a.length()>100){
            return;
        }
        for (int i = 0; i <a.length() ; i++) {
            for (int j = i+1; j <a.length() ; j++) {
                if(a.charAt(i) == a.charAt(j)){
                    a=a.substring(0,j)+a.substring(j+1,a.length());
                }
            }
        }
        System.out.println(a);
        sc.close();
    }
}
